The present invention relates to a switchgear unit with a communications capability for connection to a bus system which contains a power bus, a data bus as well as at least one auxiliary power bus. The switchgear unit, which is used for operational switching and protection of a load, includes a support and an assembly that can be mounted on this support. A bus system can be inserted into the support, and the assembly makes contact with the bus system after mounting on the support.
A switchgear unit is described in European Patent No. 0 753 916, which relates to a load feeder. The power bus, the data bus and the auxiliary power bus in this case are routed as a busbar in the base part of the load feeder, once the latter has been installed in the cubicle. This means that, for installation, it must be clear from the start which switching devices are to be provided at what point in the cubicle. The conventional busbar adapter system is used for connection of a motor feeder and has on its upper face top-hat section rails onto which a contact and/or a power breaker can be snapped. The busbar adapter system contains a trough that is composed of a base part and a trough upper part. Retaining elements for holding bus bars are provided in the base part. The trough upper part contains openings, which are protected against direct contact at the front, and which, the contacts on an adapter upper part can be passed in order to make contact with the bus bars. This is done by hooking the adapter in, and pivoting it into place.
A switch gear unit with a communications capability is described in PCT Published Patent Application No. WO 96/42188, which provides simple adaptation and contact with switching devices, in conjunction with the electronics required for data communication, for a cubicle with a data bus. The switchgear unit includes an equipment base to which a plurality of switching devices can be adapted via a standard profiled rail, as well as a communications unit, which is held on the equipment base and has plug contacts via which the switching devices are actuated electrically. The switchgear unit may include, for example, a contact and/or a power breaker. If a further switching device is required, the equipment base is expanded by adding an equipment base expansion part.
Main power connections for connection to a three-phase busbar system are located on the rear wall of the equipment base of the switchgear unit. The switchgear unit is simultaneously held and made contact with by being hooked in on the bus bars. The data is transmitted to the electronics in the communications module via a bus connector or insulation-displacement contact with a bus line, directly at the communications module.
In the case of automation devices, and as described in European Patent No. 0 236 711, it is conventional for mounting racks to be used for adaptation of input/output assemblies. The mounting racks can be snapped onto supporting rails and can be connected to one another via additional control lines. In this case, the mounting racks are designed individually as modular mounting racks having a matching circuit. A connecting block for the external wiring is mechanically connected to each mounting rack. The connecting block and mounting rack can be connected to the individual assemblies via a plug connection.
In this case, the matching circuit is in the form of a circuit board in the mounting rack. Female connecting strips for connection to male connections on the input/output assemblies are arranged on the circuit board.
The modular mounting racks are connected to one another via a male connector strip which, connected to the circuit board, is connected via a ribbon cable to which, for its part, a female connector strip is connected. The electrical connection to the male connector strip on the adjacent mounting rack can be made via this female connector strip. The mounting racks can be connected to one another, side-by-side, by hooking tabs, which project at the sides, into recesses of matching design in the enclosures of the mounting racks. The electrical connection is made independently of this. German Patent Application No. 197 34 709 describes a switchgear system having a power bus of modular construction. In this case, a plurality of switching devices are operated via the same power feeder. To do this, each switching device has an associated power bus module, which in each case has a power bus section via which the associated switching device can be electrically connected to the power feeder. In this case, the power bus sections are connected to one another to form a continuous distribution rail. The power feeder can be connected at least to one of the power bus sections.
An object of the present invention is to provide a switchgear and control unit that has a communications capability, can be expanded with little effort including the required bus system, and at the same time allows simple installation and disassembly while maintaining the protection against direct contact during connection to the power bus.
In this case, the configuration of the support as a modular base lower part with an integrated modular bus system makes it possible to expand the support system as required, while at the same time lengthening the bus system, in a single operation. This modular design allows a switchgear system to be constructed that is matched to the desired scope at that time, with only those components which are absolutely essential being used. This achieves a considerable cost saving.
The arrangement of the connections on the power bus section in a guide shaft, which at the same time centers the assembly on the base lower part for mounting and while making contact carries out the functions of mechanical and electrical connection in one operation. In this case, the required protection against direct contact is achieved by the position of the connections on the power bus section in the guide shaft. This results in safe connection and release of the connections to the power bus section, which generally has voltages of more than 100 V applied to it.
An advantageous embodiment of the present invention is obtained if the assembly is coupled to the base lower part in such a manner that partial loosening of the assembly with simultaneous disconnection of the contact with the control bus section is possible, while maintaining the connections to the power bus section.
Specifically, the early disconnection of the connections for the data bus section means that the contacts of the switchgear unit are opened, thus ensuring operational disconnection of connected loads from the power bus in all cases. This also ensures that, when the assembly is finally detached with the plug contacts to the power bus being withdrawn, this process is carried out only in a non-live state.
The coupling of the assembly is advantageously provided by a joint and/or rotating mechanism.
It is also advantageous for the base lower part to be composed of a support with the guide shaft and a module which can be coupled to it. This modular construction makes it possible to couple application-specific modules to it, that is to say to match the configuration to the actual requirements, while minimizing the cost involved. For the configuration to provide a load feeder, the module is designed as a power bus module.
A further advantage is obtained if the support is designed with an attachment element which, when operated, allows the support to be latched simultaneously on a standard profiled rail and a further support arranged in a row, in one operation.
This design contributes to a low level of installation and disassembly effort, which is a major advantage with respect to commissioning and expansion, as well as testing of the switchgear and control unit.
A particularly cost-effective design is obtained if the attachment element is designed as a spring-loaded slide with a latching tab for latching to the standard profiled rail and latching element for locking to a further support arranged in a row.
This represents a solution with a low level of parts complexity, which is advantageous in terms of the cost for production and storage. In order to withdraw the assembly from the support, it is advantageous if this assembly can be withdrawn from the base lower part via a pulling element on its front face. This allows simple, single-handed disassembly to be achieved with a compact configuration of a plurality of switchgear and control units alongside one another.
Further options for matching the switchgear unit to the respective system requirements are obtained if, on its connection side, which is intended for adaptation of the assembly, the support has recesses for accommodating contact inserts for bus expansion via which the modular bus system can be expanded, and plug inserts can be inserted into the assembly. The connection side of the plug inserts is suitable for connection to the contact inserts.
The present invention allows, optimization of the cubicle construction while at the same time including low-voltage switchgear in the automation process. The following specific tasks relating to this may be realized:
minimizing space in the cubicle,
reducing the installation cost,
simplifying the installation work,
reducing the wiring complexity for the control wiring,
reducing the wiring complexity for the main power,
reducing the test effort,
simplifying servicing.
The functions of xe2x80x9cmechanical attachment/control wiring of the switch gear/main power feeder, distribution and outgoers/switching and protection of loads/commissioning and servicingxe2x80x9d for groups of load feeders are considered and optimized for this purpose.
The solution includes a modular system which allows cubicles to be constructed simply by joining components together. The modular construction allows a switchgear system to be constructed with the actually required scope, thus resulting in a considerable cost saving.